This invention provides a plastic container component and a method of forming a plastic container component. In particular, the method of this invention is capable of forming a plastic cover having a rigid body for locking to a container and a flexible pouring spout for emptying container contents without removing the cover.
It is often desirable to provide a cover that can be locked to a container and that has a spout for dispensing container contents without removing the cover. It is also desirable in some instances to provide a nestable spout so that containers can be stacked and shipped without damaging the spout.
Conventionally, assembled fittings are attached to container covers to serve these purposes. Such spouts are typically plastic with a metal ring for crimping the spout to a molded opening in the cover. An inner edge of the molded opening typically extends above the cover surface for attachment of the spout.
For example, U.S. Pat. No. 4,236,629 to Dwinell describes a pouring spout assembly with a sealing channel that rests on the neck of a pail opening and a metal crimping ring that surrounds the sealing channel. The crimping ring is deformed to lock the spout onto the neck.
Conventional crimping methods have significant disadvantages. For example, use of a crimping ring requires an additional crimping operation that adds expense to the manufacturing operation. Also, such crimps are sometimes defective and may result in containers that leakxe2x80x94so-called xe2x80x9cleakers.xe2x80x9d
Crimping methods also require the use of a metallic ring. Such metallic components add cost and must be removed before recycling. This is a significant disadvantage in view of the current demand for recyclable products.
Additionally, crimping methods require the formation of a so-called xe2x80x9cwellxe2x80x9d in the cover so that the top of the spout is flush with the top of the cover to permit stacking and avoid spout damage. Such a well compromises drainage of container contents.
Over the years, attempts have been made to overcome disadvantages of conventional manufacturing methods. For example, U.S. Pat. No. 5,221,028 to Dwinell describes a method of forming a pail cover assembly having a plastic closure joined to a plastic cover. A welding horn is intended to fuse a portion of a closure to the underface of a pail cover. Such methods require a separate sonic welding operation that adds expense to the product.
It is an object of this invention to provide a plastic container component and a method of forming a plastic container component that overcomes the disadvantages associated with the prior art.
It is another object to provide a method that does not require a separate operation for the attachment of a spout to a container cover.
Another object is to provide a method capable of forming a reliable liquid-tight seal between a plastic spout and a cover.
Yet another object is to provide a method that does not require the use of non-plastic components in a container cover.
An additional object is to provide a method that does not require providing a well in a container cover.
Other objects will be made clear in view of the following description.
A method is provided for forming an improved plastic container component with an integral plastic preform and a liquid-tight seal along an edge of the preform. A mold is provided with a recess shaped to accommodate the preform. When closed, the mold defines a flow passage corresponding to contours of the container component. The preform is positioned within the mold recess, thereby creating a barrier with the preform between the flow passage and recess. A portion of the preform extends into the flow passage. Molten plastic is injected into the flow passage under pressure and into intimate contact with the edge of the preform. The molten plastic is cooled and a liquid-tight bond is created at the preform edge. The container component is then removed from the mold.
FIG. 1 is a cross-sectional side view of a container cover embodiment produced by a method according to this invention.
FIG. 2A is a cross-sectional side view of a flexible spout component of the container cover shown in FIG. 1.
FIG. 2B is a top view of the flexible spout component shown in FIG. 2A.
FIG. 3 is a cross-sectional side view of a mold assembly embodiment that is used in a method according to this invention.
FIG. 4 is a cross-sectional side view of a core insert component of the mold assembly shown in FIG. 3.
FIG. 5 is a cross-sectional side view of a cavity insert component of the mold assembly shown in FIG. 3.
FIG. 6 is a cross-sectional side view illustrating details of a portion of the mold assembly shown in FIG. 3.